Bottom structure for laminated ski



Allg- 25, 1964 H. E. HOLMBERG ETAL 3,145,998

BOTTOM STRUCTURE FOR LAMINATED sx1 Filed April '2, 1962 United States Patent O 3,145,998 BOTTOM STRUCTURE FOR LAMINA'IED SKI Hartvig E. Heinsberg and Harry E. Holmberg, St. Paul, Minn., assignors to Hm't Ski Mfg. Co., Ine., St. Paul, Minn., a corporation of Minnesota Filed Apr. 2, 1962, Ser. No. 184,254 9 Claims. (Cl. 28d-11.13)

This invention relates to laminated skis and more particularly to the bottom construction of such skis.

The lamination of woods and metals to form a ski with the desired exure characteristics is of common knowledge -in the prior art. The use of an exposed metal running edge on either side of the skis under surface is also of common knowledge in the prior ski art. In the wood laminated skis, the metal edge is generally comprised of narrow linkages of wear-resistant steel. The linkages are in turn countersunk into the lower running surface of the ski and then held by short screws. The ends of the metal edge linkages are interfitted into mating configurations of successively joining linkages. An edge linklage, and sometimes more, is very often ripped loose from the ski when the ski is being used. This destruction is often caused by rocks or sticks of wood, or the like, which are unintentionally traversed by the skier and which may catch the leading end of the edge linkage.

In skis made from composite materials such as metal, resin and fibrous masses, continuous edge strips are merely adhered for a narrow area and even when they are angulated or recessed they still become loosened or torn under use.

Once the running edge linkages or inserts are ripped loose, it is very diicult, and often approaches irnpossibility, to resecure the mutilated running edge to the ski bottom in such a manner that the skier thereafter can rely upon the reconstructed edge.

Hardened edge inserts, however, have .the advantage of providing a sharp running edge which makes it possible for a skier to better control his skis under both normal and difcult skiing conditions. Also, if the edge insert projects for a short distance laterally of the ski, there is excess material which can be ground down from time to time for the purpose of removing nicks and sharpening the edge.

The present invention contemplates a composite ski wherein resins are utilized for bonding and for the running area and sheet metal is utilized -for strength and resilience and constitutes an improvement over our prior United States patent for Laminated Ski, No. 2,851,277.

An object of this invention is to provide a ski bottom structure with a long-lasting metal running edge which is permanently and positively secured to the structure of the ski.

Another object of this invention is to provide a ski running edge which is of one continuous piece lof material for substantially the length of the ski and which can be economically contoured and permanently placed prior to molding.

It is a further object of this invention to provide a running edge for a ski which stresses simplicity of design ,and `construction and provides a prefabricated screed or ice or similar parts throughout the several views and in which:

FIGURE l is a side elevation of our laminated ski;

FIGURE 2 is a bottom plan view of our ski, portions thereof being segmentally layered and hidden parts shown in dotted lines;

FIGURE 3 is an enlarged segment of the bottom of the ski structure of FIGURE 2, the bottommost layer being cut away to show the internal structure of the ski and some important features of this invention, hidden portions being indicated in dotted line;

FIGURE 4 is an enlarged cross section taken on the line 4-4 of FIGURE 3;

FIGURE 5 is a further enlarged cross sectional segment of the edge construction of FIGURE 4; and

FIGURE 6 is a view similar to that of FIGURE 5 showing an alternate form of the edge construction.

With continued reference to the drawings and more particularly to FIGURES l and 2, we show our ski generally having an upper surface 10, a smooth running surface or bottom 11 and sides 12 and 13. The forward end of the ski is bent upwardly at 14, and the rearward end terminates at rear end 15. The mid-portion 16 of the ski 10 is somewhat cambered and is of greater cross section than are the ends, these features being requirements of a good ski as is well known in the ski art. As may be seen in FIGURE 2, the ski 10 has a widened portion 17 at the forward end near the curved portion 14.

The ski body or core 18 may be comprised of wood or bonded material of wood particles. The core 18 may be of a solid construction throughout or of a configuration as shown in FIGURE 4 wherein there is an open medial portion 19 which extends longitudinally and, as may be seen in FIGURE 2, extends substantially the length of the ski from a rearward termination at 20 to the forward termination at 21. We find that the ilexure properties of our ski can be easily controlled though the ski body is provided with the open medial portion 19. By the same token, we have been able to substantially reduce the weight of the ski while maintaining its strength.

A heel plate 22 of aluminum or other suitable material is positioned in the plane of the core 18 at the rear end of the ski as may be more clearly seen in FIGURE 3. This plate 22 provides a termination for the medial portion 19 as well as providing the necessary structure to prevent splitting or other damage to the heel end of the ski at end 15. In a similar manner, the forward end of the ski is provided with a toe plate 23 which provides a structural reinforcement at the curved portion 14 as well as providing a termination for the end of medial portion 19. The toe and heel portions also prevent snow or water from penetrating the interior of the ski. The toe plate 23 is ungrooved and remains a smooth curved piece of material. The heel plate 22, however, has an upwardly arched portion 24 (see FIGURE 2) which matches the shape of tracking groove 25.

The tracking groove 25, as mentioned above, extends from the rearward end 15 of the ski to termination point 26 near the forward end of the ski as may be seen in FIGURE 2. This tracking groove 2S is, of course, required for the straight line tracking of the ski when the ski is being used.

As seen in FIGURES 4 and 5, a thin, narrow side strip 27 is secured to the outside surface 28 of core members 18. The purpose of these side strips is to enhance the appearance of the ski and, if made of a hard plastic or other similarly durable material, they will add structure to the ski as well as higher resistance to scratching and marring than would the core members 18 themselves provide.

As may be further seen in FIGURE 4, we may utilize a lamination system similar to that disclosed in our prior Patent No. 2,851,277 wherein we provide our laminated ski with a first upper sheet 29, preferably of an aluminum type material, which is secured to the upper surface 30 of core members 1S, side strips 27 and end plats 22 and 23. To the top of aluminum sheet 29 is secured a second upper sheet 31 which is preferably of a thin steel composition and which is coextensive with the area of aluminum sheet 29, i.e., over the entire upper area of the ski. A final third upper sheet 32, preferably of a hard plastic material, is finally bonded to the upper surface 33 of the steel sheet 31 and is similarly coextensive with the area of steel sheet 31.

Similarly secured to the lower surface 34 of core members 18, side strips 27 and end plates 22 and 23 is a first lower sheet 35 which is substantially the same as sheet 29 in thickness, composition, and linear dimensions; however, as may be seen in FIGURE 4, a longitudinal raised portion 36 is formed in the medial portion of the sheet which provides the basic shape of groove 25.

An important feature of our invention resides in the second lower sheet 37, which is of spring steel composir tion similar to sheet 31, but has an entirely different configuration. As may be seen in FIGURE 3, this steel sheet or perforate sheet 37 has width and length identical to aluminum sheet 35 excepting at the forward upturned end of the ski 14. As shown by the dotted lines in FIGURE 2, where the ski begins to narrow, at point 38, the perforate sheet terminates.

As seen in FIGURE 3, the perforate plate 37 has a punched or perforated configuration shown generally as openings 39 which may be formed by simply punching the portions of the plate 37 out by machine. The remaining portions constitute principally an edge portion 4t) and inwardly extending fingers 41. As seen in FIGURE 3, the fingers extend inwardly and may terminate at respective ends 42 adjacent the tracking groove 25.

We find that by providing the perforate plate with a longitudinal separation defined by the ends 42 Lof fingers 41 that the perforate plate may be varied in width to accommodate the width of the ski along the ski length so that at area 17 (see FIGURE 2) where the ski widens, the perforate plate 40 (actually the lateral distance between finger ends 42) may similarly be widened thereby positioning the running edge 44 coincident with, or at a fixed distance outside the ski sides, regardless of the overall width of the ski.

Secured to the bottom surface 43 of the perforate plate 37 is a continuous and single running edge 44 on each side, which constitutes another important part of our invention. The relation of the running edge 44 to the other ski elements may be more celarly seen in FIG- URE 5.

Running edge 44 is approximately a quarter of an inch wide and extends the same length on the ski as perforate plate 37 does. We find that running edge 44, if also made of a hardened steel composition similar to that of perforate sheet 37, will provide the desired wearresistance to snow and to withstand foreign materials such as stones and sticks of wood. We have found that the running edge 44 may be easily and positively secured t perforate plate 40 by spot welding 44a. The strength of the weldment 44a exceeds that of adhesive bonding and can be accomplished in the thicknesses required without warping or destroying the hardness of the metal. We have also found that we can produce the same edge structure 44 by welding a continuous bead of weld material along the marginal edge of perforate plate 40, after which the bead is ground to the desired dimensions.

As may be seen in FIGURES 4 and 5, we provide a final running sheet 45 on the bottom of the ski which may be of a hard thermosetting resin or may be of a less hard, but more slippery, composition such as polyethylene. The thickness of sheet 45 is substantially that of the running edges 44 so that a smooth continuous running surface, lying in a single plane, is formed by utilizing the running edges as screeds or stop guides so that the lower surface 46 of the ski is defined by running edges 44 and running sheet 45. Where portions of perforate plate 37 have been eliminated, such as open portion 39 between fingers 41, the groove portion 47 and the portion 48 which is between the forward end termination 49 of plate 37 and the ski tip 50, the thickness of sheet 45 is additionally the thickness of the perforate plate 37. The open space 39 defined by fingers 41 of perforate plate 37 allows the plastic sheet material to fiow into the open spaces during the construction process and thereby to form a key system 51 for interlocking and bonding the running sheet 45, the fingers 41 and sheet 35 together.

An alternate form of edge construction is shown in FIGURE 6. The upper portion 52 of the ski may be similar to, or even identical with, the upper portion of the ski as described above. The bottom structure, however, differs somewhat below the first metal plate 53 which lies immediately below the core 54.

In the alternate form, the running edge 55 has a right angled shape with a horizontal flange 56 underlying the edge margin 57 of plate 53 and a vertical ange 58 extending downward to provide a sharp running edge 59 and a horizontal guide surface 60 at the bottom thereof. Flange 56 has an upwardly facing surface 61 adapted to be bonded to the marginal surface 57 of plate 53 and has a downwardly facing surface 62 which overlies the spring steel plate 63 at its upper marginal surface 64.

The steel plate 63 corresponds to plate 37 of the first disclosed form and may have perforate openings of various design formed therethrough as previously disclosed. In any event a substantial portion of the plate 63, in the form of solid plate, fingers, bridging strips, or the like underlies a plate 65 which, in turn, is bonded to the plate 53 and provides a spacing function so that all of the plates and the running edge are adapted to be bonded together.

This arrangement makes possible the face-to-face abutment of plate 63 underneath the flange 56. The respective faces 64 and 62 are then spot welded at frequent intervals 66 for the length of the running edge 55 to create an extremely strong juncture. It will be noted that the juncture itself is shielded by the vertical ange 58 which projects downwardly for a short distance beyond the steel plate 63. It will be further noted that plate 63 and running edge 55 can be properly shaped and welded in advance of the completion of the ski so that no temporary holding elements or adhesive need be employed. The shallow recess which is defined by the downward flange extensions 58 of running edges 55 and the plate 63 becomes a cavity within which a suitable material such as a wax modified polyethylene 67 can be molded and bonded. The surface 60 of each edge fiange extension 58 defines a guide or stop for molding the running surface 67 within the cavity.

From the foregoing, it is readily seen that we have devised an improved bottom structure for a composite ski which has a strong and durable running edge of simple construction, and which performs multiple functions in both the fabrication and use of the ski.

It will, of course, be understood that various changes may be made in the form, details, arrangements and proportions of the parts without departing from the scope of our invention as set forth in the appended claims.

What is claimed is:

1. In a laminated ski, a bottom structure therefor comprising a hard continuous sheet of weldable metal bonded as a laminate thereto, said sheet extending substantially for the length and substantially for the width of said ski, right angled running edge means also of weldable metal at each side of said sheet, each of said running edge means having an inwardly directed horizontal flange and a downwardly directed vertical flange, said horizontal fianges being welded directly to marginal portions of said r sheet to form a channel-shaped unit composed of said sheet and running edge means, and a running sheet having at least a substantial portion of its upper face bonded to the lower face of said metal sheet between said running edge means whereby to form a smooth continuous surface with said running edge means.

2. A ski having a bottom as set forth in claim 1 in which said metal sheet and said running edge means are of hardened steel.

3. A ski having a bottom as set forth in claim 2 in which said horizontal flanges are spot welded at spaced locations therealong to said metal sheet.

4. In a laminated ski, a bottom structure therefor comprising a steel sheet bonded as a laminate thereto, said sheet extending substantially for the length and slightly less than the width of the said ski and having continuous side edges, right angled steel running edge means at each side of said sheet, each of said edge means having a horizontal flange overlying the upper marginal portions of said sheet and the lower surface of each flange being secured by welding to said upper marginal portions of said sheet and each edge means having a vertical ange extending downwardly therefrom, and a running sheet bonded to the lower face of said steel sheet between said running edge means to form a smooth continuous surface with said running edge means.

5. A ski having a bottom a's set forth in claim 4 in which said horizontal flanges are spot welded at spaced locations therealong to said metal sheet.

6. A ski having a bottom as set forth in claim 4 in which the combined thicknesses of said steel and running sheets is substantially equal to the downwardly extending length of each vertical flange.

7. A ski having a bottom as set forth in claim 4 in which said steel sheet has openings formed therethrough.

8. In a laminated ski, core material, a first metal sheet bonded to the underside of said core material, a plurality of right angled steel running edge means, each of said edge means having a horizontal flange and a vertical flange, the upper faces of said horizontal flanges being bonded to the lower marginal portions of said rst sheet, a second metal sheet extending between said horizontal ilanges having its upper face bonded to the central lower portion of said rst sheet, a steel sheet having its upper marginal portions spot welded to the undersides of said horizontal flanges at spaced locations therealong and its upper central portion bonded to the underside of said second sheet, and a running sheet bonded to the lower face of said steel sheet between said vertical flanges to form a smooth continuous surface with said running edge means.

9. A ski as set forth in claim 8 in which each steel sheet is provided with openings extending through the central portion thereof.

References Cited in the le of this patent UNITED STATES PATENTS 1,973,343 Hansen Sept. 11, 1934 2,446,591 Hoerle Aug. 10, 1948 2,581,532 Hen Jan. 8, 1952 2,648,543 Grabowski Aug. 11, 1953 2,694,580 Head Nov. 16, 1954 2,851,277 Holmberg et al Sept. 9, 1958 FOREIGN PATENTS 204,885 Switzerland Aug. 1, 1939 218,934 Austria Dec. 27, 1961 631,879 Great Britain NOV. 11, 1949 979,589 France Dec. 13, 1950 

1. IN A LAMINATED SKI, A BOTTOM STRUCTURE THEREFOR COMPRISING A HARD CONTINUOUS SHEET OF WELDABLE METAL BONDED AS A LAMINATE THERETO, SAID SHEET EXTENDING SUBSTANTIALLY FOR THE LENGTH AND SUBSTANTIALLY FOR THE WIDTH OF SAID SKI, RIGHT ANGLED RUNNING EDGE MEANS ALSO OF WELDABLE METAL AT EACH SIDE OF SAID SHEET, EACH OF SAID RUNNING EDGE MEANS HAVING AN INWARDLY DIRECTED HORIZONTAL FLANGE AND A DOWNWARDLY DIRECTED VERTICAL FLANGE, SAID HORIZONTAL FLANGES BEING WELDED DIRECTLY TO MARGINAL PORTION OF SAID SHEET TO FORM A CHANNEL-SHAPED UNIT COMPOSED OF SAID SHEET AND RUNNING EDGE MEANS, AND A RUNNING SHEET HAVING AT LEAST A SUBSTANTIAL PORTION OF ITS UPPER FACE BONDED TO THE LOWER FACE OF SAID METAL SHEET BETWEEN SAID RUNNING EDGE MEANS WHEREBY TO FORM A SMOOTH CONTINUOUS SURFACE WITH SAID RUNNING EDGE MEANS. 